This invention relates to a drill with insert and, more particularly, to a novel carbide insert having a unique perimeter consisting of six sides.
Inserts of this general type can be seen in U.S. Pat. No. 4,230,429 wherein the six sided insert has six equal sides arranged in three pairs. This type of insert is subject to the limitation of being used in only short length bores. The invention is based upon the discovery that the provision of unequal length sides in each pair, the forces operating on the bit are better balanced and therefore a longer bore hole can be achieved.
The invention is described in conjunction with the accompanying drawing, in which
FIG. 1 is an elevational view of the elongated drill;
FIG. 2 is an end view of the drill of FIG. 1;
FIG. 3 is an enlarged front elevational view of one of the inserts seen at the bottom of FIG. 1;
FIG. 4 is a side elevational view of the insert of FIG. 3;
.FIG. 5 is a sectional view taken along the sight line 5--5 applied to FIG. 3;
FIG. 6 is a fragmentary elevational view of a modified form of drill but essentially similar to that of FIG. 1 but in which cartridges are used to support the inserts--this being applicable for larger diameter drills;
FIG. 7 is an end view of the drill of FIG. 6;
FIG. 8 is an enlarged sectional view of the cartridge seen in FIG. 7;
FIG. 9 is an enlarged elevational view of the cartridge lock of FIGS. 7 and 8; and
FIG. 10 is an end view of the cartridge lock of FIG. 9.